Business process architectures allow to organize business processes and their relations. The entity-centric approach for business process modeling may offer new insights on this field. We present an entity-centric procedure for deriving a business process architecture baseline using the following core ideas: (i) domain model entities may be interpreted as business entities at a higher level of abstraction than usually used by entity-centric approaches, (ii) domain model relationships provide useful information for deriving a business processes architecture. We present the procedure in combination with an application example. The resulting business process architecture baseline specifies: (i) decomposition, specialization, and trigger relations, and (ii) core and support classification of business processes. These results show the potential of our approach. The main contribution of our work is providing guidelines to obtain business process architectures that may be used as reference models for companies within the same industry.